This is part of a series called Wine Words, a glossary in the works that breaks down the barrier between those in the wine know and those who have no idea what the hell everyone's talking about. A new word posts once a week, covering everything from a grape name or region, to a winemaking or tasting term.
Sulfur & Sulfites (n.) Winemaking Term
There's a lot of talk about sulfites in wine, allergies to sulfites and, as a result, a search for sulfite-free wines. The situation is a little bit complicated, but let's break it down in its simplest form.
Sulfur is a naturally occurring element, part of Earth's crust, with a yellow color and, in large quantities, a rotten egg odor. I'm sure you've seen pictures of sulfur, probably in science class back in the day, or as natural sulfur hot springs in National Geographic. Sulfur dioxide is the chemical compound formed when sulfur is burned in air: one molecule of sulfur + 2 molecules oxygen. Both forms, sulfur and sulfur dioxide, have been used in winemaking for sterilizing and preserving since the ancient days of yore, primarily by burning sulfur to cleanse barrels and vessels in preparation for fermentation, and to prevent wine from turning to vinegar. These are still the two basic needs SO2 meets today.
As a natural antimicrobial, sulfur might be used in vineyards to fight fungus issues like powdery mildew. At crush, which immediately follows harvest, sulfur might be used to prevent fermentation from beginning on its own (spontaneous or natural fermentation) and to a debatable degree, oxidation. Finally, winemakers typically add SO2 to the finished wine at bottling as a preservative. The use of sulfur when and to what degree has become a controversial subject in recent years, especially when it comes to organic and natural wines. The most diehard natural wine producers refuse any added sulfur, which can result in volatile wines that might undergo a number of reactions that throw unpleasant or difficult to understand aromas.
Then there's the matter of sulfites, a blanket term that includes free sulfur dioxide, sulfurous acid, bisulfite ion and sulfite ion. Thus the creation of the law-bound labelling term, "Contains Sulfites." Sulfite allergies are debatable. Some evidence shows only asthmatics to be at risk, the effect being on the airways, not the head. Histamines, mostly found in red wine, are considered to be the potential headache culprits, but there are so many other factors and chemical compounds to consider when a "reaction" occurs, this too is debatable.
All wine contains some traces of naturally occurring sulfur. No wine is completely sulfite-free.
Confused? Yup, it's complex.
If you think you might be allergic to sulfites, you're probably not. But if you're one of the estimated .05% of the population that is, you probably already know sulfites are commonly used to preserve dried fruit, fruit juices, baked goods, canned vegetables, shrimp, dehydrated potatoes, and raw-packaged chicken and meats.
All that said, the philosophy behind when and in what quantities to use sulfites in winemaking is a direct extension of the winemaker's beliefs. Big and mega producers making huge quantities of wine, especially brands that create a reliable vintage-averse product that tastes more or less the same year after year after year, are likely to use more sulphur, and use it more often. Can't risk losing market share! As always at Pig&Vine, we look for the little guys, the ones whose life is wine, the ones who farm organically and take a personal, hands-on approach to making wine. This goes for all regions on the planet, but here's an insider tip for you: The European Union maximum allowances are the lowest, with organic wines (meaning grapes grown organically) having even lower allowances.
In short, know your winemaker (as much as possible), kinda like know your farmer. Better living, Better Drinking.